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Merge branch kvm-arm64/fpsimd-tracking into kvmarm-master/next 

* kvm-arm64/fpsimd-tracking:
  : .
  : Simplify the handling of both the FP/SIMD and SVE state by
  : removing the need for mapping the thread at EL2, and by
  : dropping the tracking of the host's SVE state which is
  : always invalid by construction.
  : .
  arm64/fpsimd: Document the use of TIF_FOREIGN_FPSTATE by KVM
  KVM: arm64: Stop mapping current thread_info at EL2
  KVM: arm64: Introduce flag shadowing TIF_FOREIGN_FPSTATE
  KVM: arm64: Remove unused __sve_save_state
  KVM: arm64: Get rid of host SVE tracking/saving
  KVM: arm64: Reorder vcpu flag definitions

Signed-off-by: Marc Zyngier <maz@kernel.org>
This commit is contained in:
Marc Zyngier 2021-12-01 12:13:44 +00:00
parent e525523c19 31aa126de8
commit 2d761dbf7f
9 changed files with 40 additions and 81 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
arch/arm64/include/asm/kvm_host.h
View File

@ -26,7 +26,6 @@
#include <asm/fpsimd.h>
#include <asm/kvm.h>
#include <asm/kvm_asm.h>
#include <asm/thread_info.h>
#define __KVM_HAVE_ARCH_INTC_INITIALIZED
@ -321,7 +320,6 @@ struct kvm_vcpu_arch {
struct kvm_guest_debug_arch vcpu_debug_state;
struct kvm_guest_debug_arch external_debug_state;
struct thread_info *host_thread_info; /* hyp VA */
struct user_fpsimd_state *host_fpsimd_state; /* hyp VA */
struct {
@ -408,20 +406,17 @@ struct kvm_vcpu_arch {
#define KVM_ARM64_DEBUG_DIRTY (1 << 0)
#define KVM_ARM64_FP_ENABLED (1 << 1) /* guest FP regs loaded */
#define KVM_ARM64_FP_HOST (1 << 2) /* host FP regs loaded */
#define KVM_ARM64_HOST_SVE_IN_USE (1 << 3) /* backup for host TIF_SVE */
#define KVM_ARM64_HOST_SVE_ENABLED (1 << 4) /* SVE enabled for EL0 */
#define KVM_ARM64_GUEST_HAS_SVE (1 << 5) /* SVE exposed to guest */
#define KVM_ARM64_VCPU_SVE_FINALIZED (1 << 6) /* SVE config completed */
#define KVM_ARM64_GUEST_HAS_PTRAUTH (1 << 7) /* PTRAUTH exposed to guest */
#define KVM_ARM64_PENDING_EXCEPTION (1 << 8) /* Exception pending */
/*
* Overlaps with KVM_ARM64_EXCEPT_MASK on purpose so that it can't be
* set together with an exception...
*/
#define KVM_ARM64_INCREMENT_PC (1 << 9) /* Increment PC */
#define KVM_ARM64_EXCEPT_MASK (7 << 9) /* Target EL/MODE */
#define KVM_ARM64_DEBUG_STATE_SAVE_SPE (1 << 12) /* Save SPE context if active */
#define KVM_ARM64_DEBUG_STATE_SAVE_TRBE (1 << 13) /* Save TRBE context if active */
#define KVM_GUESTDBG_VALID_MASK (KVM_GUESTDBG_ENABLE | \
KVM_GUESTDBG_USE_SW_BP | \
KVM_GUESTDBG_USE_HW | \
KVM_GUESTDBG_SINGLESTEP)
/*
* When KVM_ARM64_PENDING_EXCEPTION is set, KVM_ARM64_EXCEPT_MASK can
* take the following values:
@ -439,11 +434,14 @@ struct kvm_vcpu_arch {
#define KVM_ARM64_EXCEPT_AA64_EL1 (0 << 11)
#define KVM_ARM64_EXCEPT_AA64_EL2 (1 << 11)
/*
* Overlaps with KVM_ARM64_EXCEPT_MASK on purpose so that it can't be
* set together with an exception...
*/
#define KVM_ARM64_INCREMENT_PC (1 << 9) /* Increment PC */
#define KVM_ARM64_DEBUG_STATE_SAVE_SPE (1 << 12) /* Save SPE context if active */
#define KVM_ARM64_DEBUG_STATE_SAVE_TRBE (1 << 13) /* Save TRBE context if active */
#define KVM_ARM64_FP_FOREIGN_FPSTATE (1 << 14)
#define KVM_GUESTDBG_VALID_MASK (KVM_GUESTDBG_ENABLE | \
KVM_GUESTDBG_USE_SW_BP | \
KVM_GUESTDBG_USE_HW | \
KVM_GUESTDBG_SINGLESTEP)
#define vcpu_has_sve(vcpu) (system_supports_sve() && \
((vcpu)->arch.flags & KVM_ARM64_GUEST_HAS_SVE))
@ -736,6 +734,7 @@ long kvm_vm_ioctl_mte_copy_tags(struct kvm *kvm,
/* Guest/host FPSIMD coordination helpers */
int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu);
void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu);
void kvm_arch_vcpu_ctxflush_fp(struct kvm_vcpu *vcpu);
void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu);
void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu);

1
arch/arm64/include/asm/kvm_hyp.h
View File

@ -90,7 +90,6 @@ void __debug_restore_host_buffers_nvhe(struct kvm_vcpu *vcpu);
void __fpsimd_save_state(struct user_fpsimd_state *fp_regs);
void __fpsimd_restore_state(struct user_fpsimd_state *fp_regs);
void __sve_save_state(void *sve_pffr, u32 *fpsr);
void __sve_restore_state(void *sve_pffr, u32 *fpsr);
#ifndef __KVM_NVHE_HYPERVISOR__

6
arch/arm64/kernel/fpsimd.c
View File

@ -78,7 +78,11 @@
* indicate whether or not the userland FPSIMD state of the current task is
* present in the registers. The flag is set unless the FPSIMD registers of this
* CPU currently contain the most recent userland FPSIMD state of the current
* task.
* task. If the task is behaving as a VMM, then this is will be managed by
* KVM which will clear it to indicate that the vcpu FPSIMD state is currently
* loaded on the CPU, allowing the state to be saved if a FPSIMD-aware
* softirq kicks in. Upon vcpu_put(), KVM will save the vcpu FP state and
* flag the register state as invalid.
*
* In order to allow softirq handlers to use FPSIMD, kernel_neon_begin() may
* save the task's FPSIMD context back to task_struct from softirq context.

1
arch/arm64/kvm/arm.c
View File

@ -856,6 +856,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
}
kvm_arm_setup_debug(vcpu);
kvm_arch_vcpu_ctxflush_fp(vcpu);
/**************************************************************
* Enter the guest

46
arch/arm64/kvm/fpsimd.c
View File

@ -7,7 +7,6 @@
*/
#include <linux/irqflags.h>
#include <linux/sched.h>
#include <linux/thread_info.h>
#include <linux/kvm_host.h>
#include <asm/fpsimd.h>
#include <asm/kvm_asm.h>
@ -28,24 +27,13 @@ int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu)
{
int ret;
struct thread_info *ti = &current->thread_info;
struct user_fpsimd_state *fpsimd = &current->thread.uw.fpsimd_state;
/*
* Make sure the host task thread flags and fpsimd state are
* visible to hyp:
*/
ret = create_hyp_mappings(ti, ti + 1, PAGE_HYP);
if (ret)
goto error;
/* Make sure the host task fpsimd state is visible to hyp: */
ret = create_hyp_mappings(fpsimd, fpsimd + 1, PAGE_HYP);
if (ret)
goto error;
if (!ret)
vcpu->arch.host_fpsimd_state = kern_hyp_va(fpsimd);
vcpu->arch.host_thread_info = kern_hyp_va(ti);
vcpu->arch.host_fpsimd_state = kern_hyp_va(fpsimd);
error:
return ret;
}
@ -55,26 +43,27 @@ error:
*
* Here, we just set the correct metadata to indicate that the FPSIMD
* state in the cpu regs (if any) belongs to current on the host.
*
* TIF_SVE is backed up here, since it may get clobbered with guest state.
* This flag is restored by kvm_arch_vcpu_put_fp(vcpu).
*/
void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu)
{
BUG_ON(!current->mm);
BUG_ON(test_thread_flag(TIF_SVE));
vcpu->arch.flags &= ~(KVM_ARM64_FP_ENABLED |
KVM_ARM64_HOST_SVE_IN_USE |
KVM_ARM64_HOST_SVE_ENABLED);
vcpu->arch.flags &= ~KVM_ARM64_FP_ENABLED;
vcpu->arch.flags |= KVM_ARM64_FP_HOST;
if (test_thread_flag(TIF_SVE))
vcpu->arch.flags |= KVM_ARM64_HOST_SVE_IN_USE;
if (read_sysreg(cpacr_el1) & CPACR_EL1_ZEN_EL0EN)
vcpu->arch.flags |= KVM_ARM64_HOST_SVE_ENABLED;
}
void kvm_arch_vcpu_ctxflush_fp(struct kvm_vcpu *vcpu)
{
if (test_thread_flag(TIF_FOREIGN_FPSTATE))
vcpu->arch.flags |= KVM_ARM64_FP_FOREIGN_FPSTATE;
else
vcpu->arch.flags &= ~KVM_ARM64_FP_FOREIGN_FPSTATE;
}
/*
* If the guest FPSIMD state was loaded, update the host's context
* tracking data mark the CPU FPSIMD regs as dirty and belonging to vcpu
@ -104,13 +93,11 @@ void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu)
void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu)
{
unsigned long flags;
bool host_has_sve = system_supports_sve();
bool guest_has_sve = vcpu_has_sve(vcpu);
local_irq_save(flags);
if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED) {
if (guest_has_sve) {
if (vcpu_has_sve(vcpu)) {
__vcpu_sys_reg(vcpu, ZCR_EL1) = read_sysreg_el1(SYS_ZCR);
/* Restore the VL that was saved when bound to the CPU */
@ -120,7 +107,7 @@ void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu)
}
fpsimd_save_and_flush_cpu_state();
} else if (has_vhe() && host_has_sve) {
} else if (has_vhe() && system_supports_sve()) {
/*
* The FPSIMD/SVE state in the CPU has not been touched, and we
* have SVE (and VHE): CPACR_EL1 (alias CPTR_EL2) has been
@ -134,8 +121,7 @@ void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu)
sysreg_clear_set(CPACR_EL1, CPACR_EL1_ZEN_EL0EN, 0);
}
update_thread_flag(TIF_SVE,
vcpu->arch.flags & KVM_ARM64_HOST_SVE_IN_USE);
update_thread_flag(TIF_SVE, 0);
local_irq_restore(flags);
}

6
arch/arm64/kvm/hyp/fpsimd.S
View File

@ -25,9 +25,3 @@ SYM_FUNC_START(__sve_restore_state)
sve_load 0, x1, x2, 3
ret
SYM_FUNC_END(__sve_restore_state)
SYM_FUNC_START(__sve_save_state)
mov x2, #1
sve_save 0, x1, x2, 3
ret
SYM_FUNC_END(__sve_save_state)

30
arch/arm64/kvm/hyp/include/hyp/switch.h
View File

@ -29,7 +29,6 @@
#include <asm/fpsimd.h>
#include <asm/debug-monitors.h>
#include <asm/processor.h>
#include <asm/thread_info.h>
struct kvm_exception_table_entry {
int insn, fixup;
@ -49,7 +48,7 @@ static inline bool update_fp_enabled(struct kvm_vcpu *vcpu)
* trap the accesses.
*/
if (!system_supports_fpsimd() ||
vcpu->arch.host_thread_info->flags & _TIF_FOREIGN_FPSTATE)
vcpu->arch.flags & KVM_ARM64_FP_FOREIGN_FPSTATE)
vcpu->arch.flags &= ~(KVM_ARM64_FP_ENABLED |
KVM_ARM64_FP_HOST);
@ -143,16 +142,6 @@ static inline bool __populate_fault_info(struct kvm_vcpu *vcpu)
return __get_fault_info(vcpu->arch.fault.esr_el2, &vcpu->arch.fault);
}
static inline void __hyp_sve_save_host(struct kvm_vcpu *vcpu)
{
struct thread_struct *thread;
thread = container_of(vcpu->arch.host_fpsimd_state, struct thread_struct,
uw.fpsimd_state);
__sve_save_state(sve_pffr(thread), &vcpu->arch.host_fpsimd_state->fpsr);
}
static inline void __hyp_sve_restore_guest(struct kvm_vcpu *vcpu)
{
sve_cond_update_zcr_vq(vcpu_sve_max_vq(vcpu) - 1, SYS_ZCR_EL2);
@ -169,21 +158,14 @@ static inline void __hyp_sve_restore_guest(struct kvm_vcpu *vcpu)
*/
static bool kvm_hyp_handle_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code)
{
bool sve_guest, sve_host;
bool sve_guest;
u8 esr_ec;
u64 reg;
if (!system_supports_fpsimd())
return false;
if (system_supports_sve()) {
sve_guest = vcpu_has_sve(vcpu);
sve_host = vcpu->arch.flags & KVM_ARM64_HOST_SVE_IN_USE;
} else {
sve_guest = false;
sve_host = false;
}
sve_guest = vcpu_has_sve(vcpu);
esr_ec = kvm_vcpu_trap_get_class(vcpu);
/* Don't handle SVE traps for non-SVE vcpus here: */
@ -207,11 +189,7 @@ static bool kvm_hyp_handle_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code)
isb();
if (vcpu->arch.flags & KVM_ARM64_FP_HOST) {
if (sve_host)
__hyp_sve_save_host(vcpu);
else
__fpsimd_save_state(vcpu->arch.host_fpsimd_state);
__fpsimd_save_state(vcpu->arch.host_fpsimd_state);
vcpu->arch.flags &= ~KVM_ARM64_FP_HOST;
}

1
arch/arm64/kvm/hyp/nvhe/switch.c
View File

@ -25,7 +25,6 @@
#include <asm/fpsimd.h>
#include <asm/debug-monitors.h>
#include <asm/processor.h>
#include <asm/thread_info.h>
#include <nvhe/fixed_config.h>
#include <nvhe/mem_protect.h>

1
arch/arm64/kvm/hyp/vhe/switch.c
View File

@ -24,7 +24,6 @@
#include <asm/fpsimd.h>
#include <asm/debug-monitors.h>
#include <asm/processor.h>
#include <asm/thread_info.h>
/* VHE specific context */
DEFINE_PER_CPU(struct kvm_host_data, kvm_host_data);